The Pentagon ordered a fleet of war ships to the coast of Yemen Monday, including the aircraft carrier USS Theodore Roosevelt, the guided-missile cruiser USS Normandy and several destroyers carrying special boarding teams,

The ships have been deployed to secure the shipping lanes passing through the Bab al-Mandab strait, according to official Pentagon spokesman Colonel Steve Warren.

According to an anonymous Pentagon source cited by Reuters, however, the real purpose of the deployment is to confront Iranian ships allegedly seeking to deliver aid to the Houthi insurgents who seized power in the country in January.

Pressed by reporters about the purpose of the naval deployments, White House spokesman Josh Earnest referred to US worries over “continued support for the Houthis” by Iran.

“We have seen evidence that the Iranians are supplying weapons and other armed support to the Houthis in Yemen. That support will only contribute to greater violence in that country. These are exactly the kind of destabilizing activities that we have in mind when we raise concerns about Iran’s destabilizing activities in the Middle East,” he said.

The US Navy has already massed at least seven other combat ships in the Gulf of Aden and the Arabian Sea in support of the mission. Amphibious ships prepositioned with this fleet are carrying US Marine Corps ground units that can be landed on short notice.

The denunciations of Iranian “destabilizing activities” come from a government that has played an active role in supporting the Saudi-led bombing campaign in Yemen from the beginning,

The deployments mark a further deepening of US intervention in the war against Yemen and point to the possibility of a direct conflict between the US and Iran. US imperialism is upping the ante even as the one-month-old Saudi-led bombardment of the country is creating a devastating humanitarian catastrophe.

Massive explosions rocked the Yemeni capital at Sanaa on Monday, flattening residential areas and killing scores while producing explosions compared by witnesses to an earthquake. Small clouds rose over the outskirts of the city, where air strikes had targeted major weapons deposits and missile bases. Ambulances lined approaches to nearby hospitals, according to reports.

Heavy strikes continued Friday and over the weekend, with warplanes and missiles of the Saudi-led coalition targeting Sanaa, Taiz and Aden. Saudi coalition strikes have destroyed civilian neighborhoods, factories and businesses across the country, according to witnesses cited in US media.

Some 750-1,000 Yemenis have been killed during the Saudi-led air campaign, according to UN estimates, with thousands more wounded. Hundreds of thousands of Yemenis have been displaced from their homes in Yemen as a result of the air campaign.

“All the signs are that things are worsening,” said Adrian Edwards, a spokesman for the UN.

“Basic services are on the verge of collapse. It’s just getting worse by the day.”

While Riyadh claims that the savage bombing of Yemen is needed to restore the “legitimate” US- and Saudi-backed government led by President Abd Rabbuh Mansur Hadi, in reality the massacre of Yemen’s population is the product of a regional power struggle between Saudi Arabia and Iran that is intensifying under the impact of the efforts of US imperialism to maintain its dominance throughout the Middle East and Central Asia.

The war has the potential to ignite a war between a US-backed coalition of Egypt, Saudi Arabia and the Gulf states on one side and Iran, which has cultivated relations with America’s main geopolitical rivals China and Russia, on the other. Russia refused to vote for a UN resolution that would have banned arms shipments to the Houthis, and the country has resumed sales of advanced anti-aircraft missiles to Iran itself.

There have already been warnings that the Arab coalition, dominated by the militaries of Saudi Arabia and Egypt, which have been lavishly funded and armed by the US, may have ambitions stretching beyond Yemen, including intervention against pro-Iranian militias in Iraq, Syria and Lebanon. Saudi and Egypt began joint military exercises in the Arabian peninsula last week, staged as a prelude to a ground invasion of Yemen. Suggesting that the joint Saudi-Egyptian force might soon be used in Iraq and elsewhere, Iraqi Prime Minister Haider al-Abadi accused the Saudi regime of using the crisis in Yemen to pursue a region-wide confrontation with Iran along sectarian lines.

Meanwhile, large areas of the country have fallen to the Sunni extremist group Al Qaeda in Arabian Peninsula (AQAP), the suppression of which was the officially stated purpose of US involvement in the country.

AQAP has consolidated control over oil fields, with remaining government forces suffering repeated defeats at the hands of AQAP, the Houthis and other militant groups. On Friday, a Yemeni army unit transferred control over a large oil field to a coalition of tribal militias for “safekeeping” after AQAP militants approached the area, seizing a nearby army base and expanding their area of control around the port city of Al Mukalla.

Iranian calls for a ceasefire in Yemen and the formation of a unity government were summarily dismissed last week by Riyadh, which is suspicious of Iranian efforts to cut a deal with the White House. Envoys from the Gulf states rejected calls from UN head Ban Ki-moon for a ceasefire in Yemen Monday,